Airflow-straightening structure for the nacelle of an aircraft engine

ABSTRACT

An airflow-straightening structure for an aircraft engine is provided that includes a hoop inside which there are arranged a plurality of flow-straightening vanes bearing a hub of a fan. Also includes is a clevis for connecting to a suspension strut, the clevis being fixed to said hoop. The structure has at least two elements chosen from the group of the hoop, the plurality of vanes, the hub and the clevis, which are formed in one piece, that is to say without any assembly operation. Additionally, at least one of the elements chosen from the group is at least partially formed of a composite material.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of International Application No.PCT/FR2011/051379 filed on Jun. 16, 2011, which claims the benefit of FR10/54852, filed on Jun. 18, 2010. The disclosures of the aboveapplications are incorporated herein by reference.

FIELD

The present disclosure relates to an airflow-straightening structure foran aircraft engine.

BACKGROUND

The statements in this section merely provide background informationrelated to the present disclosure and may not constitute prior art.

As is known in itself, and shown in the appended FIG. 1, a nacellehaving axis A for a dual-flow (turbojet) engine traditionally comprisesan outer structure 1 having an upstream portion 3 forming an air intake,an intermediate portion 5 whereof the inner skin 6 forms a case for thefan 7 of the engine, and a downstream portion 9 that may incorporatethrust reversal means.

This nacelle also includes an inner structure 11 having a fairing 13 forthe engine 15.

The outer structure 1 defines, with the inner structure 11, an annularair duct 17, often called “cold air duct,” as opposed to the hot aircreated by the engine 15.

The fan 7 essentially consists of a propeller provided with blades 19,which are rotatably mounted on a stationary hub 21 connected to the fancase 6 by a plurality of stationary arms 25, which may for example bedistributed at 120 degree intervals.

Upstream of these stationary arms are airflow-straightening vanes 23,also called OGV (“Outlet Guide Vanes”), which make it possible tostraighten the cold air flow created by the fan 7.

SUMMARY

The present disclosure provides an airflow-straightening structure foran aircraft engine, comprising:

-   -   a hoop inside which there are arranged a plurality of        flow-straightening vanes bearing a hub of a fan, and    -   a clevis for connecting to a suspension strut, said clevis being        fixed to said hoop,

the structure being remarkable in that at least two of the elementschosen from the group consisting of said hoop, said plurality of vanes,said hub and said clevis are formed in one piece, that is to say withoutany assembly operation,

and for the fact that at least one of the elements chosen from the groupconsisting of said hoop, said plurality of vanes, said hub and saidclevis is at least partially formed of composite material.

Having at least two of the aforementioned elements (hoop, vanes, hub,clevis) made in a single piece makes it possible to limit the number ofassembly operations to be carried out during assembly of the nacelle,and having at least one of those four elements made from a compositematerial enables savings in terms of weight.

According to other optional features of this structure according to theinvention:

-   -   all of said elements are made in a single piece and from a        composite material: in this way, the ease of assembly and weight        reduction are optimized;    -   the hoop incorporates the case of said fan;    -   the hoop incorporates an air intake shroud for the nacelle;    -   the hoop incorporates a thrust reverser cascade edge: these        various arrangements make it possible to still further reduce        the number of parts.

The present disclosure also relates to a nacelle for an aircraft engine,remarkable in that it comprises an airflow-straightening structure asdescribed above.

Further areas of applicability will become apparent from the descriptionprovided herein. It should be understood that the description andspecific examples are intended for purposes of illustration only and arenot intended to limit the scope of the present disclosure.

DRAWINGS

In order that the disclosure may be well understood, there will now bedescribed various forms thereof, given by way of example, referencebeing made to the accompanying drawings, in which:

FIG. 1 is a longitudinal half-section view of a nacelle and engineassembly of the prior art, described in the preamble of thisdescription;

FIG. 2 is a perspective view of an airflow-straightening structureaccording to the present disclosure; and

FIG. 3 is a detailed cross-sectional view of an engine equipped with anairflow-straightening structure according to one particular form of thepresent disclosure, and the associated nacelle portion.

In all of the figures, identical or similar references designateidentical or similar members or sets of members.

It will also be noted that a three-axis reference has been provided inthese figures showing the X, Y and Z axes. These three axes respectivelyrepresent the longitudinal, transverse and vertical directions of theengine when it is installed on an aircraft.

The drawings described herein are for illustration purposes only and arenot intended to limit the scope of the present disclosure in any way.

DETAILED DESCRIPTION

The following description is merely exemplary in nature and is notintended to limit the present disclosure, application, or uses. Itshould be understood that throughout the drawings, correspondingreference numerals indicate like or corresponding parts and features.

FIG. 2 shows that the airflow-straightening structure according to theinvention may comprise a plurality of airflow-straightening vanes 23extending between a radially inner wheel 27 and a radially outer wheel29, these vanes and wheels thus forming a flow-straightening grid.

The wheel with the larger diameter 29 is designed to be fixed orintegrated inside a hoop 31 that is part of the inner skin of theintermediate portion 5 of the outer structure 1 of the engine.

The wheel with the smaller diameter 27 bears the stationary hub 21 onwhich the fan 7 is rotatably mounted.

Fixed on the upper portion of the hoop 31 is a clevis 33 for suspendingthe nacelle from a support strut secured to the structure of anaircraft: this clevis makes it possible to connect the nacelle and itsassociated engine 15 to the aircraft.

In one form, the airflow-straightening vanes 23 and the wheels 27, 29are formed in a single piece.

Also, the hub 21 on the one hand and the assembly formed by the hoop 31and the clevis 33 on the other hand are also formed in a single piece.

At least some of said members are made from a composite material, forexample by weaving.

Still more preferably, the aforementioned set of members, i.e. the hub21, the vanes 23, the wheels 27, 29, the hoop 31 and the yoke 33, areformed in a single piece, and from a composite material.

This makes it possible to obtain a multi-functional piece with anoverall weight much lower than the set of parts it replaces, and notrequiring any assembly operation.

As can be understood from the preceding, the fact that the hub 21 of thefan 7 is borne directly by the airflow-straightening vanes 23 makes itpossible to do away with the support arms for that hub, which arepresent in the nacelles according to the prior art: savings are thusprocured in terms of structural simplicity and weight.

FIG. 3 shows a detailed view of the upstream portion of a nacelle andpart of the engine which are equipped with an airflow-straighteningstructure according to the invention, and shows that the hoop 31 canincorporate a fan case 6 and the air intake shroud 35.

As a reminder, the air intake shroud 35 is a substantially cylindricalpiece forming the inner skin of the air intake 3, on which soundabsorption panels 37 are attached that can typically have a honeycombstructure, so as to form Helmholtz resonators.

The hoop 31 can also incorporate, in the downstream portion thereof, anextension 37 forming a cascade edge, i.e. defining one of the walls ofthe channel making it possible to guide the cold airflow toward theoutside of the nacelle during implementation of the thrust reversalmeans (not shown).

As will be understood, the additional integration of the fan case 6, theshroud 35 and the cascade edge 37 in the flow-straightening structureaccording to the invention also allows increased structural simplicity,as well as weight savings when the set of parts is made in a singlepiece and from a composite material.

Of course, the present disclosure is in no way limited to theembodiments described and shown, which have been provided solely asexamples.

What is claimed is: 1 An airflow-straightening structure for an aircraftengine, comprising: a hoop inside which there are arranged a pluralityof flow-straightening vanes bearing a hub of a fan; and a clevis forconnecting to a suspension strut, said clevis being fixed to said hoop,the structure being characterized in that at least two elements chosenfrom a group consisting of said hoop, said plurality of vanes, said huband said clevis are formed in one piece, that is to say without anyassembly operation, and in that at least one of the elements chosen fromthe group consisting of said hoop, said plurality of vanes, said hub andsaid clevis is at least partially formed of a composite material.
 2. Thestructure according to claim 1, characterized in that all of saidelements are made in a single piece and from a composite material. 3.The structure according to claim 1, characterized in that said hoopincorporates the case of said fan.
 4. The structure according to claim1, characterized in that said hoop incorporates an air intake shroud. 5.The structure according to claim 1, characterized in that said hoopincorporates a thrust reverser cascade edge.
 6. A nacelle for anaircraft engine, characterized in that it comprises anairflow-straightening structure according to claim 1.